javaweb demo（basedao）

最新推荐文章于 2023-12-19 18:00:58 发布

转载最新推荐文章于 2023-12-19 18:00:58 发布 · 228 阅读

本文介绍了一个用于简化Java中数据库操作的基类BaseDao。该类通过读取配置文件完成数据库连接参数的初始化，并提供了获取数据库连接、执行查询与更新操作的方法。

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database.properties配置

driver=com.mysql.jdbc.Driver
#在和mysql传递数据的过程中，使用unicode编码格式，并且字符集设置为utf-8
url=jdbc:mysql://127.0.0.1:3306/smbms?useUnicode=true&characterEncoding=utf-8
user=root
password=root

baseDao类

package cn.smbms.dao;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

/**
* 操作数据库的基类--静态类
* @author Administrator
*
*/
public class BaseDao {

static{//静态代码块,在类加载的时候执行
  init();
}

private static String driver;
private static String url;
private static String user;
private static String password;

//初始化连接参数,从配置文件里获得
public static void init(){
  Properties params=new Properties();
  String configFile = "database.properties";
  InputStream is=BaseDao.class.getClassLoader().getResourceAsStream(configFile);
  try {
   params.load(is);
  } catch (IOException e) {
   e.printStackTrace();
  }
  driver=params.getProperty("driver");
  url=params.getProperty("url");
  user=params.getProperty("user");
  password=params.getProperty("password");
  System.out.println(user);

}

/**
* 获取数据库连接
* @return
*/
public static Connection getConnection(){
  Connection connection = null;
  try {
   Class.forName(driver);
   connection = DriverManager.getConnection(url, user, password);
  } catch (Exception e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }

  return connection;
}
/**
* 查询操作
* @param connection
* @param pstm
* @param rs
* @param sql
* @param params
* @return
*/
public static ResultSet execute(Connection connection,PreparedStatement pstm,ResultSet rs,
   String sql,Object[] params) throws Exception{
  pstm = connection.prepareStatement(sql);
  for(int i = 0; i < params.length; i++){
   pstm.setObject(i+1, params[i]);
  }
  rs = pstm.executeQuery();
  return rs;
}
/**
* 更新操作
* @param connection
* @param pstm
* @param sql
* @param params
* @return
* @throws Exception
*/
public static int execute(Connection connection,PreparedStatement pstm,
   String sql,Object[] params) throws Exception{
  int updateRows = 0;
  pstm = connection.prepareStatement(sql);
  for(int i = 0; i < params.length; i++){
   pstm.setObject(i+1, params[i]);
  }
  updateRows = pstm.executeUpdate();
  return updateRows;
}

/**
* 释放资源
* @param connection
* @param pstm
* @param rs
* @return
*/
public static boolean closeResource(Connection connection,PreparedStatement pstm,ResultSet rs){
  boolean flag = true;
  if(rs != null){
   try {
    rs.close();
    rs = null;//GC回收
   } catch (SQLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    flag = false;
   }
  }
  if(pstm != null){
   try {
    pstm.close();
    pstm = null;//GC回收
   } catch (SQLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    flag = false;
   }
  }
  if(connection != null){
   try {
    connection.close();
    connection = null;//GC回收
   } catch (SQLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    flag = false;
   }
  }

  return flag;
}

}